Agricultural plant cutting and harvesting machines typically have a header which is desired or required to be positioned at one or more selectable cutting heights in relation to the surface, and angles of sideward tilt in relation to the machine itself, as well as to a surface over which the machine is driven. When the header is positioned at a cutting height above the surface, such that the stalks of crops are left at a higher level, the machine is operating in what is sometimes referred to as a “stubble mode”. Conventional ground sensing capability is generally only useful when the header is positioned very close to, or on, the surface. Thus typical ground sensing capability, if present at all, is unavailable or inoperable when the machine is operating in the stubble mode.
When the machine is disposed on a laterally inclined surface, downward and sideward forces acting on it can result in tire deformation, ground compaction, and the like on the downhill side. It has been observed that these forces can cause the machine to tilt to a lateral tilt angle that is different, usually greater, than an angle of the laterally inclined surface. Unless tilted relative to the machine, the header is disposed at the same lateral tilt angle resulting in a downhill side of the header riding closer to the surface than an uphill side of the header.
For shorter headers and/or very small differences between the machine tilt angle and the angle of inclination of the surface, the height difference at the ends of the header may not present a problem. However, for longer headers this angular difference causes a more pronounced height difference at the ends of the header such that the downhill side of the header may ride significantly closer to the surface than the uphill side. In some circumstances, this may lead to undesirably uneven cutting height and risks possible damage to the cutting apparatus due to impact with the ground. In this situation an operator typically provides an uphill tilt correction to compensate for the undesired sideward or transverse tilt angle of the header.
It is known to use an inclinometer to provide a lateral tilt angle at which the machine is operating for use with a self-leveling grain cleaning system within the machine. It is desirable to use the lateral tilt angle of the machine provided by the inclinometer to model or predict the lateral tilt angle of the inclined surface so as to provide automatic compensation of the header tilt angle to maintain desired cutting height, to reduce the possibility of damage to the cutting apparatus of the header, and to reduce operator workload.
Thus, what is sought is an automatic lateral tilt control system and method for a header for a plant cutting machine which overcomes one or more of the shortcomings and limitations set forth above.